<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title></title>
    <link rel="stylesheet" type="text/css" href="../static/login_page/css/style.css"/>
    <script src="../static/jquery-3.6.0.js"></script>
    <style>
		body{
			margin:0 auto;
			overflow:hidden;
		}
		.canvaszz{
			position:absolute;
			background-image: url(img/21.jpg);
			background-size: 100%;
			width:100%;
			height:100%;
			z-index:-1;
			filter:alpha(opacity=20);
		    opacity: 0.4;
		}
		.canvas {
			position:absolute;
			display:inline-block;
			width:100%;
			height:auto;
			vertical-align:baseline;
			z-index:-2;
		}


    </style>
</head>
<body>

<div class="login-box">
    <h2>Login</h2>
    <form id="loginForm" name="loginForm" method="post">
        <div class="login-field">
            <input type="text" name = "username" id = "username" required=""/>
            <label>Username</label>
        </div>
        <div class="login-field">
            <input type="password" name = "password" id ="password" required=""/>
            <label>Password</label>
        </div>
        <button id="submit-btn" type="button">Submit</button>
    </form>
</div>
<div class="canvaszz"></div>
<canvas id="canvas" class="canvas"></canvas>

</body>
<script>
    $("#submit-btn").click(function(){
    var formObject = {};
    var formArray = $("#loginForm").serializeArray();
    $.each(formArray,function(i,item){
        formObject[item.name] = item.value;
    });
    $.ajax(
    {
        data: JSON.stringify(formObject),
        type: 'POST',
        url:"/login",
        contentType: 'application/json',
        dataType: "json",
        success: function (result) {
                        <!--后续可改为状态码-->
                        if(result.err_msg){
                            alert("请检查用户名和密码是否填写正确")
                        }
                        if(result.success == "true"){
                        date=new Date()
                        date.setTime(date.getTime()+(10*24*60*60*1000));
                        var expires = "expires="+date.toGMTString();
	                    document.cookie = "pj_login="+escape(result.token)+"; expires="+expires+"; path=/";
                        window.location.href="/";
                        }
                        if(result.success == "false"){
                            alert("用户名或密码错误")
                        }
                        if(result.exception =="true"){
                            alert("服务器错误")
                        }
                    },
        error: function(result) {
                        console.log(result);
                     }
    }
    );
})
</script>

<script>
		drawStars();
		//画星空背景
		function drawStars() {
			var canvas = document.getElementById('canvas'),
				ctx = canvas.getContext('2d'),
				w = canvas.width = window.innerWidth,
				h = canvas.height = window.innerHeight,

				hue = 217, //色调色彩
				stars = [], //保存所有星星
				count = 0,  //用于计算星星
				maxStars = 1300; //星星数量

			//canvas2是用来创建星星的源图像，即母版，
			//根据星星自身属性的大小来设置
			var canvas2 = document.createElement('canvas'),
				ctx2 = canvas2.getContext('2d');
			canvas2.width = 100;
			canvas2.height = 100;
			//创建径向渐变，从坐标(half，half)半径为0的圆开始，
			//到坐标为(half,half)半径为half的圆结束
			var half = canvas2.width / 2,
				gradient2 = ctx2.createRadialGradient(half, half, 0, half, half, half);
			gradient2.addColorStop(0.025, '#CCC');
			//hsl是另一种颜色的表示方式，
			//h->hue,代表色调色彩，0为red，120为green，240为blue
			//s->saturation，代表饱和度，0%-100%
			//l->lightness，代表亮度，0%为black，100%位white
			gradient2.addColorStop(0.1, 'hsl(' + hue + ', 61%, 33%)');
			gradient2.addColorStop(0.25, 'hsl(' + hue + ', 64%, 6%)');
			gradient2.addColorStop(1, 'transparent');

			ctx2.fillStyle = gradient2;
			ctx2.beginPath();
			ctx2.arc(half, half, half, 0, Math.PI * 2);
			ctx2.fill();

			// End cache
			function random(min, max) {
				if(arguments.length < 2) {
					max = min;
					min = 0;
				}

				if(min > max) {
					var hold = max;
					max = min;
					min = hold;
				}

				//返回min和max之间的一个随机值
				return Math.floor(Math.random() * (max - min + 1)) + min;
			}

			function maxOrbit(x, y) {
				var max = Math.max(x, y),
					diameter = Math.round(Math.sqrt(max * max + max * max));
				//星星移动范围，值越大范围越小，
				return diameter / 2;
			}

			var Star = function() {
				//星星移动的半径
				this.orbitRadius = random(maxOrbit(w, h));
				//星星大小，半径越小，星星也越小，即外面的星星会比较大
				this.radius = random(60, this.orbitRadius) / 8;
				//所有星星都是以屏幕的中心为圆心
				this.orbitX = w / 2;
				this.orbitY = h / 2;
				//星星在旋转圆圈位置的角度,每次增加speed值的角度
				//利用正弦余弦算出真正的x、y位置
				this.timePassed = random(0, maxStars);
				//星星移动速度
				this.speed = random(this.orbitRadius) / 50000;
				//星星图像的透明度
				this.alpha = random(2, 10) / 10;

				count++;
				stars[count] = this;
			}

			Star.prototype.draw = function() {
				//星星围绕在以屏幕中心为圆心，半径为orbitRadius的圆旋转
				var x = Math.sin(this.timePassed) * this.orbitRadius + this.orbitX,
					y = Math.cos(this.timePassed) * this.orbitRadius + this.orbitY,
					twinkle = random(10);

				//星星每次移动会有1/10的几率变亮或者变暗
				if(twinkle === 1 && this.alpha > 0) {
					//透明度降低，变暗
					this.alpha -= 0.05;
				} else if(twinkle === 2 && this.alpha < 1) {
					//透明度升高，变亮
					this.alpha += 0.05;
				}

				ctx.globalAlpha = this.alpha;
				//使用canvas2作为源图像来创建星星，
				//位置在x - this.radius / 2, y - this.radius / 2
				//大小为 this.radius
				ctx.drawImage(canvas2, x - this.radius / 2, y - this.radius / 2, this.radius, this.radius);
				//没旋转一次，角度就会增加
				this.timePassed += this.speed;
			}

			//初始化所有星星
			for(var i = 0; i < maxStars; i++) {
				new Star();
			}

			function animation() {
				//以新图像覆盖已有图像的方式进行绘制背景颜色
				ctx.globalCompositeOperation = 'source-over';
				ctx.globalAlpha = 0.5; //尾巴
				ctx.fillStyle = 'hsla(' + hue + ', 64%, 6%, 2)';
				ctx.fillRect(0, 0, w, h)

				//源图像和目标图像同时显示，重叠部分叠加颜色效果
				ctx.globalCompositeOperation = 'lighter';
				for(var i = 1, l = stars.length; i < l; i++) {
					stars[i].draw();
				};

				//调用该方法执行动画，并且在重绘的时候调用指定的函数来更新动画
				//回调的次数通常是每秒60次
				window.requestAnimationFrame(animation);
			}

			animation();
		}


</script>
</html>